I liked it when they stuck to geography. The champions of each regional would the championship team of that region of the country and you could have great post-season rivalries between the major conferences of the region. The Final Four was a meeting of champions. They ended that because of the UCLA dynasty. People though the Bruins had a competitive advantage out west. But, let's face it, those UCLA teams didn't need it. Wooden was 20-2 in the Final Four, (not counting consolation games). He had a competitive advantage over the entire country.
You would need to reduce the field, cap conferences at 5 teams to make it fair, and figure out where conferences go. Adding more quality to the NIT wouldn't be a bad thing. Look at the Europa league recently.
East (9)- Big East, ACC, America East, A10, CAA, Ivy, MAAC, NEC, Patriot
South (10)- SEC, AAC, ASUN, Big South, CUSA, MEAC, Southern, Southland, SWAC, Sun Belt
Midwest (6)- B1G, Horizon, MAC, MVC, OVC, Summit
West (7)- B12, P12, Big Sky, Big West, MWC, WAC, WCC
Those are pretty much right regionally except for the B12. They probably should be South but then the West is too weak, especially after realignment.
So this year would be something like...
East
1. Marquette vs 16. FDU
2. Xavier vs 15. Colgate
3. UVA vs 14. Princeton
4. UConn vs 13. Vermont
5. Duke vs 12. Iona
6. Creighton vs 11. Charleston
7. Miami vs 10. Providence
8. NC St vs 9. VCU
South
1. Houston vs 16. North Texas
2. Bama vs 15. Texas Southern
3. Tennessee vs 14. A&M CC
4. Kentucky vs 13. Howard
5. A&M vs 12. UNC Asheville
6. Missouri vs 11. Kennesaw St
7. Memphis vs 10. Louisiana
8. FAU vs 9. Furman
Midwest
1. Purdue vs 16. Cleveland St
2. Indiana vs 15. Indiana St
3. Northwestern vs 14. Morehead St
4. Michigan St 13. Youngstown St
5. Iowa vs 12. Bradley
6. Drake vs 11. Toledo
7. Oral Roberts vs 10. SEMO
8. Kent St vs 9. Northern Kentucky
West
1. Kansas vs 16. UC Santa Barbara
2. UCLA 15. Montana St
3. Texas vs 14. Grand Canyon
4. Zona vs 13. Utah St
5. Gonzaga vs 12. TCU
6. Baylor vs 11. USC
7. K State vs 10. Boise St
8. San Diego St vs 9. Saint Mary's
If you notice that Midwest is hard to find enough teams. The following teams would have been in the NIT instead:
ISU, MD, Arkansas, Illinois, Auburn, WV, Penn St, Miss St, Pitt, Arizona St, Nevada
Besides Iowa St those are all 8-11 seeds so it isn't the worst thing in the world to send them to the NIT, which all of a sudden is a better field.